Secure digital cards and embedded multimedia cards are pervasively used as
secondary storage devices in portable electronics, such as smartphones and
tablets. These devices cost under 70 cents per gigabyte. They deliver more than
4000 random IOPS and 70 MBps of sequential access bandwidth. Additionally, they
operate at a peak power lower than 250 milliwatts. However, software storage
stack above the device level on most existing mobile platforms is not optimized
to exploit the low-energy characteristics of such devices. This paper examines
the energy consumption of the storage stack on mobile platforms.

We conduct several experiments on mobile platforms to analyze the energy
requirements of their respective storage stacks. Software storage stack consumes
up to 200 times more energy when compared to storage hardware, and the security
and privacy requirements of mobile apps are a major cause. A storage energy model
for mobile platforms is proposed to help developers optimize the energy
requirements of storage intensive applications. Finally, a few optimizations are
proposed to reduce the energy consumption of storage systems on these
platforms.